Exhaust system for marine propulsion device



Spt. 16, W- J. SHIMANCKAS EXHAUST SYSTEM FOR MARINE PROPULSION DEVICE Filed March 30. 1967 2 Sheets-Sheet 1 693/. 2 575/ 2f fr @III/infila);

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EXHAUST SYSTEM FOR MARINE PROPULSION DEVICE Filed March 30, 1967 2 Sheets-Sheet 2 il@ nier/5f United States Patent O 3,467,051 EXHAUST SYSTEM FOR MARINE PROPULSION DEVICE William J. Shimanckas, Waukegan, Ill., assignor to Outboard Marine Corporation, Waukegan, Ill., a corporation of Delaware Filed Mar. 30, 1967, Ser. No. 627,116 Int. Cl. B63h 21/14, 1/20 U.S. Cl. 115-34 16 Claims ABSTRACT OF THE DISCLOSURE l Disclosed herein is a marine propulsion lower unit which is arranged to afford exhaust gas discharge during forward drive through a discharge outlet at the rear of a propeller hub, and when operating under conditions other than in forward drive, to provide underwater exhaust gas discharge upstream from the exhaust gas discharge outlet at the rear of the propeller.

Background of invention In the past, marine propulsion devices with lower units arranged to afford exhaust gas discharge through the propeller hub and into the propeller slip stream have been commonly used. Such arrangements suffer from the disadvantage that, during reverse operation, the exhaust gases are discharged into the water through which the propeller is biting, thereby tending to create conditions of ventilation or cavitation and reducing the ethciency of the propeller.

Summary of invention Drawings FIGURE 1 is a fragmentary view, partially in section, of a marine propulsion device embodying various of the features of the invention;

FIGURE 2 is an enlarged fragmentary view, partially in section, of the propulsion device shown in FIGURE 1 with certain components in another position;

FIGURE 3 is a fragmentary view, partially in section, of another embodiment of the invention which is similar to the embodiment shown in FIGURES l and 2; and

FIGURE 4 is a fragmentary view, partially in section, of the device shown in FIGURE 3 with certain components in another position;

FIGURE 5 is a fragmentary view, partially in section, of another marine propulsion device embodying various of the features of the invention;

FIGURE 6 is a fragmentary view, partially in section, of the device shown in FIGURE 5 with certain components in different positions;

FIGURE 7 is a fragmentary view, partially in section, of another marine propulsion device embodying various of the features of the invention; and

FIGURE 8 is a fragmentary view, partially in section, of the device shown in FIGURE 7 with certain components in different positions.

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General description Shown in FIGURE 1 is a fragmentarily illustrated marine propulsion device 11 including a lower unit 13 which can be vertically and horizontally swingably mounted to a boat hull. As is conventional, the lower unit 13 includes a drive shaft housing 15 having, at the lower end thereof, a gear case 17 in which there is rotatably mounted a propeller shaft 19. The lower unit also conventionally includes an exhaust gas passageway 23 which extends through the drive shaft housing 15 and terminates, at the rearward end of the gear case 17, in an exhaust gas discharge port 25 through which extends the propeller shaft 19. As is conventional, the propeller shaft can be connected for forward drive, rearward drive, and neutral by a clutch mechanism (not shown). Carried on the propeller shaft 19 for rotation therewith is a propeller 27 having a hub 29 and a plurality of blades 31 mounted on the hub, each blade having a forward face 31a and a rearward face 31b. As is also known, the propeller 27 includes an inner sleeve portion 30 which is connected to the hub 29 by a plurality of radially extending ribs 32 and which, together with the hub 29, defines an axially extending exhaust gas duct 33 provided, at its forward end, with an inlet 34 and, at its rearward end, with a discharge opening or outlet 35 rearward of the propeller blades 31. The exhaust gas duct 33 is located in position for communication of the inlet 34 with the exhaust gas port 25 to afford exhaust gas flow from the engine (not shown) through the exhaust gas passageway 23 in the lower unit 13, and through the exhaust gas duct 33 in the propeller 27 for exit through the rearward discharge opening 35.

In accordance with the invention, there is provided means for affording underwater exhaust gas discharge forwardly of the rear face of the propeller blades when the propeller shaft is operating in rearward drive condition.

While various arrangements can be employed, in the disclosed constructions, there is provided means affording axially shifting of the propeller relative to the discharge port between a position wherein the lower unit discharge port and the inlet are in direct communication and a second position wherein the discharge port and an inlet are in spaced relation to each other.

Also in accordance with the invention, in the embodiment as shown in FIGURE 1, the mounting of the propeller 27 on the propeller shaft 19 is such as to freely afford axial movement of the propeller 27 on the propeller shaft 19 relative to the discharge port 25 between a first position affording direct communication of the exhaust gas duct 33 with the discharge port 25 and a second more rearwardly located position (see FIG. 2) in which the propeller hub 29 is spaced from the discharge port to afford an annular opening or outlet 37 facilitating exhaust gas discharge forwardly of the discharge opening 35 at the rear of the propeller hub 29.

Accordingly, when the propeller 27 is driven for forward propulsion, the water reaction will displace the propeller 27 forwardly on the propeller shaft 19 until the exhaust gas discharge port 25 and the forward portion of the propeller hub 29 are in partially telescopic relation to each other (FIG. 1), thereby affording direct communication. Under such circumstances, exhaust gas is discharged through the discharge opening 35 into the propeller slip stream rearwardly of the propeller Iblades 31. However, when the propeller shaft 19 is rotated to provide rearward drive, the water reaction displaces the propeller 27 rearwardly on the propeller shaft 19 to provide an annular exhaust gas outlet 37 (FIG. 2) forwardly of the propeller blades 31 between the propeller hub 29 and the exhaust gas discharge port 25, thereby affording exhaust gas discharge into the propeller slip stream and not through the discharge opening 35 into the water into which the propeller 27 bites during rearward drive conditions.

Various means can be employed to afford axial shifting of the propeller 27 on the propeller shaft 19, while also affording rotary driving connection between the propeller shaft 19 and the propeller 27. In the disclosed construction, such means is in the form of complementary splines 39 on each of the propeller shaft 19 and the sleeve portion 30.

Means are provided for limiting travel of the propeller 27 on the propeller shaft 19. While various means can be employed, in the disclosed construction, such means is in the form of stops axially spaced at a distance greater than the length of the hub to afford withdrawal of the propeller hub 4 from telescopic relation to discharge port 35 and to provide the annular outlet 37 with sucient length to facilitate exhaust gas discharge when in reverse. Specifically, the propeller shaft is provided with a annular shoulder or stop 41 which is located forwardly of the splines 39 and which is engaged by the sleeve portion 30 to limit forward propeller movement and to establish the forward drive position of the propeller 27.

Rearward propeller movement is limited by a washer or stop 43 which is seated against a shoulder 45 on the propeller shaft 19 by a nut 47 and which extends radially to afford engagement by the sleeve portion 30 and thereby establish the rearward drive position of the propeller 27.

The propeller hub 29 and the discharge port 25 are provided with cooperating means for preventing exhaust gas escape therebetween when in telescopic relation. While various arrangements can be employed, in the disclosed construction, such means is in the form of a labynnth seal formed by a series of facing annular grooves 51 on the internal Wall of the discharge port 25 and on the external wall of the forward periphery of the propeller hub 29.

If desired, means can be provided for closing the exhaust gas discharge opening 35 when the propeller 27 is displaced to its rearward position to preclude exhaust gas discharge from the opening 35. Thus, in the construction shown in FIGURE 3, the washer 43a extends radially outwardly for engagement with the outer annular wall of the hub 29, thereby closing fthe opening 35 when the propeller 27 is in its rearwardmost position. It is noted, that in the arrangement shown in FIGURE 4, when the propeller 29 is in its forward drive position there is provided an annular exhaust gas discharge area or outlet 53 which lhas a greater axial length than the annular outlet 37 afforded when the propeller 29 is in its rearward drive position.

Other arrangement can also be employed for effecting axial shifting of the propeller relative to the exhaust gas discharge port of the lower unit. For instance, means can be provided for axially shifting the propeller shaft carrying the propeller so as to afford movement of the propeller relative to the lower unit discharge port. In addition, such shifting of the propeller shaft can also be employed to afford shifting of a clutch mechanism. Thus, in the construction shown in FIGURES 5 and 6, there is disclosed a marine propulsion device 111 including a lower unit 113 having an exhaust gas passageway 123 terminating in a discharge port 135. The lower unit 113 includes a gear case 117 into which there extends a drive shaft 157 carrying a drive bevel pinion 159 forming a part of a clutch mechanism 161. Meshed with the pinion 159 are a pair of bevel gears 1'63 and 165 which are rotatably mounted on a propeller shaft 119 extending through the discharge port 135. Fixedly mounted on fthe propeller shaft 119 is a propeller 127 with a hub 129, a plurality of blades 131 extending from said hub 129, and an axial exhaust gas duct 133 which extends through said hub 129 and terminates at a rearward discharge opening 135.

In accordance with the invention, means are provided in the gear case 117 for mounting the propeller shaft 119 for rotary movement and for axial movement whereby to rotatably drive the propeller shaft 119, while affording movement of the propeller 129 relative to the lower unit exhaust gas discharge port between a first position (see FIG. 5) associated with forward drive operation wherein the propeller hub 129 and lower unit discharge port 125 are partially telescopically related so as to afford exhaust gas discharge through the propeller hub outlet rearwardly of the propeller blades 131, and a second position (see FIG. 6) associated with rearward or reverse drive operation and located rearwardly of the first position wherein the hub 129 is withdrawn from telescopic relation to the lower unit discharge port 135 to provide an annular exhaust opening or outlet 137 between the lower unit housing 115 and the propeller hub 129. In the disclosed construction, such mounting means comprises a pair of spaced bearings 169 and 171. The bearing 169 is carried by the gear case 117 forwardly of the clutch member 161 and the bearing 171 is carried by a support member 173 located rearwardly of the clutch mechanism 161.

Means are also provided for axially shifting the propeller shaft 119 and, if desired, for coordinating such shifting with operation of the clutch mechanism 161 controlling transmission of rotary power from the bevel gears 163 and 165 to the propeller shaft 119. More particularly, the propeller shaft 119 includes an annular groove 175 which receives one leg 177 of a bell crank lever which forms a part of a mechanical actuating linkage and which is pivotally mounted to the lower unit housing 115. The other end or leg 181 of the bell crank lever 179 is connected to a push rod or actuating link 183 such as has been commonly employed in the past to control clutch operation.

In this last regard, shifting of the clutch mechanism 161 in coordination with the axial movement of the propeller shaft 119 is afforded by means of one or more dogs or lugs 185 which are fixed to the propeller shaft 119 and which, in response to axial propeller shaft movement, are selectively positionable in a first or forward position (FIG. 5) drivingly engaging the bevel gear 163 to the propeller shaft 119, a second or rearward position (FIG. 6) drivingly engaging the bevel gear 165 to the propeller shaft 119, and a third or intermediate position wherein the dogs 185 are out of engagement with both bevel gears 163 and 165 and the drive is in neutral.

As in the embodiment shown in FIGURE l, the lower unit discharge port 125 and the propeller hub 129 are provided with means for preventing the escape of exhaust gas when the propeller hub 129 and the lower unit discharge port are telescopically related. While various arrangements can be employed, in the disclosed construction such means is in the series of annular oppositely facing grooves 151 on the inner wall of the lower unit discharge port 125 and on the outer wall of the propeller hub 129.

In operation, when the actuating link 183 is displaced upwardly from the position shown in FIGURE 5, the propeller shaft 119 is displaced to the right, thereby disengaging the dogs 185 from the bevel gear 163 to provide a neutral position wherein neither of the bevel gears 163 and 165 is drivingly connected to the propeller shaft 119. Such rearward movement of the propeller shaft 119 also serves to at least partially withdraw the propeller hub 129 from telescopic relation to the lower unit discharge port 125.

Further upward movement of the actuating link 183 serves to displace the propeller shaft sufficiently rearwardly so as to engage the dogs 185 with the bevel gear 165, thereby providing a rearward drive condition. Such rearward movement of the propeller shaft 119 also serves to separate the propeller hub 129 from the lower unit discharge port 128 so as to provide an annular exhaust gas outlet 137 forwardly of the propeller blades 131.

Shown in FIGURES 7 and 8 is still another embodiment of the invention, which embodies an axially shiftable propeller shaft 219 and which is similar to the embodiments of FIGS. 5 and 6 except that the propeller shaft is biased into forward drive position andl axial propeller shifting is accomplished by a hydraulic actuator. More particularly, in the embodiment shown in FIGURES 5, 7, and 8, the propeller shaft 219 is biased forwardly by suitable means into the forward drive position and into engagement with a hydraulic actuator 291 which serves both to effect shifting of the clutch mechanism 161 and selective location of the propeller hub 29 relative to the lower unit exhaust gas discharge port 25. Various arrangements can be employed to provide the propeller shaft biasing means. In the disclosed construction, there is employed a helical spring 293 contained between a snap ring 295 mounted on the propeller shaft 219 and a seat 297 adjacent to a shoulder on a propeller bearing support member 273. The disclosed biasing means provides the disclosed device wlth a fail-safe feature. Specifically, in the event of loss of hydraulic pressure in the actuator 291, the spring 293 will serve to assure that the drive is in forward position.

Various hydraulic actuators can be employed. In the disclosed construction, the actuator 291 includes a piston 299 having a stub shaft 201 which is rounded at its rearward end and engaged against the forward end of the propeller shaft 219 to facilitate rotation of the propeller shaft 219 relative thereto with a minimum of friction. The specific details of the hydraulic actuator are not believed to be a part of this invention, except to the extent that the actuator should be capable of affording piston movement suicient to effect axial propeller shaft movement either merely to displace the propeller between forward and rearward positions or to accommodate shifting through forward, rearward and neutral conditions, in addition to affording propeller movement. Reference is hereby made to my corresponding application Serial No. 627,106, filed March 30, 1967 for one hydraulic actuator or mechanism which can be employed.

Various other arrangements can be employed to obtain at least some of the advantages of the invention by affording means for discharging exhaust gases forwardly of the propeller blades and into the water when operating in reverse drive. For instance, mechanically operated ports could be formed in the lower housing and subject to opening upon the reverse drive engagement in order to afford escape beneath water level of the exhaust gases in an area forwardly of the rearward end of the propeller and preferably forwardly of the propeller blades.

Various of the features of the invention are set forth in the following claims.

I claim:

1. In a marine propulsion device comprising a lower unit including an exhaust gas discharge passageway terminating in an exhaust gas discharge port, a rotatably mounted propeller shaft extending through said port, a clutch mechanism selectively connecting said propeller shaft in forward drive and in rearward drive and a propeller mounted on said propeller shaft for rotation therewith and including a blade having a rear face and an exhaust gas passageway having an inlet communicating with said exhaust gas discharge port and an outlet rearwardly of said blade, the improvement in combination therewith comprising means for affording underwater exhaust gas discharge through said port and into the water around said lower unit forwardly of the rear face of said propeller blade when said device is in reverse drive.

2. A device in accordance with claim 1 including means for preventing exhaust gas discharge through said outlet when said device is in said reverse drive.

3. In a marine propulsion device comprising a lower unit including an exhaust gas discharge passageway terminating in an exhaust gas discharge port, a rotatably mounted propeller shaft extending through said port, and a propeller mounted on said propeller shaft for rotation therewith and including an exhaust gas duct having an inlet located in a position directly communicating with said exhaust gas discharge port, the improvement in combination therewith comprising means for affording axially shifting of said propeller relative to said discharge port between said position wherein said discharge port and said inlet are in direct communication and a second position wherein said discharge port and said inlet are in spaced relation to each other to provide an opening for exhaust gas discharge forwardly of said propeller.

4. A marine propulsion device according to claim 3 wherein said means for affording axial shifting of said propeller relative to said discharge port comprises cooperating means on said propeller shaft and on said propeller affording axial shifting of said propeller on said propeller shaft.

5. A marine propulsion device in accordance with claim 3 wherein said means for affording axial shifting of said propeller relative to said discharge port comprises means mounting said propeller shaft on said lower unit for axial movement relative to said lower unit, and means on said lower unit and on said propeller shaft for axially shifting said propeller relative to said discharge port.

6. A device in accordance with claim 5, wherein said means for axially shifting said propeller shaft comprises a mechanical linkage.

7. A device in accordance with claim 5 wherein said means for axially shifting said propeller shaft includes a hydraulic actuator.

8. A device in accordance with claim 7 including means biasing said propeller shaft into said position affording direct communication between said inlet and said lower unit exhaust gas discharge port and into engagement with said hydraulic actuator.

9. A marine propulsion device comprising a lower unit including a vertically extending drive shaft having a driving pinion, an exhaust gas discharge passageway terminating in an exhaust gas discharge port, a rotatably mounted propeller shaft extending through said port, a pair of gears meshed with said pinion and rotatably mounted in spaced relation on said propeller shaft, and a propeller mounted on said propeller shaft for rotation threrewith and including an exhaust gas passageway having an inlet located in a position directly communicating with said exhaust gas discharge port, the improvement in combination therewith comprising dog means fixed on said propeller shaft for selective engagement with said gears in response to axial shifting of said propeller shaft ot afford selective rotation of said propeller shaft by said drive shaft in forward and rearward drives, and means for axially shifting said propeller shaft relative to said lower unit between a first position wherein said dog means is engaged with one of said gears to afford forward drive and said discharge port and said inlet are in direct communication and a second position wherein said dog means is engaged with the other of said gears to afford reverse drive and said discharge port and said inlet are in spaced relation to each other to provide an opening for exhaust gas discharge forwardly of said propeller.

10. A device in accordance with claim 9, wherein said means for axially shifting said propeller shaft comprises a mechanical linkage.

11. A device in accordance with claim 9, wherein said means for axially shifting said propeller shaft includes a hydraulic actuator.

12. A device in accordance with claim 11 including means biasing said propeller shaft into said position affording direct communication between said inlet and said lower unit exhaust gas discharge port and into engagement with said hydraulic actuator.

13. In a marine propulsion device comprising a lower unit including a vertically extending drive shaft housing having an exhaust gas discharge passageway terminating in an exhaust gas discharge port, a rotatably mounted propeller shaft extending through said port, and a propel- 1er mounted on said propeller shaft for rotation there- With and including an exhaust gas passageway having an inlet located in a position directly communicating with said exhaust gas discharge port, the improvement in combination therewith comprising means for axially shifting said propeller shaft relative to said lower unit between a rst position wherein said discharge port and said inlet are in direct communication and a second position wherein said discharge port and said inlet are in spaced relation to each other to provide an opening for exhaust gas discharge forwardly of said propeller.

14. A device in accordance with claim 13, wherein said means for axially shifting said propeller shaft comprises a mechanical linkage.

15. A device in accordance with claim 13, wherein said means for axially shifting said propeller shaft includes a hydraulic actuator.

16. A device in accordance with claim 15 including means biasing said propeller shaft into said position affording direct communication between said inlet and said lower unit exhaust gas discharge port and into engagement with said hydraulic actuator.

References Cited UNITED STATES PATENTS TRYGVE M. BLIX, Primary Examiner U.S. Cl. X.R. 1 15-17 Notice of Adverse Decisions in Interferences In Interference No. 97,498 involving Patent No. 3,467,051, W. J. Shimanckas, EXHAUST SYSTEM FOR MARINE PROPULSION DEVICE, n2a1 j ud'ment adverse to the patent/ee was rendered Mar. 28, 1973, as to claims 1, ,3am 4.

[Ojiez'a Gazette October 23,1973] 

